Not sure if OBD-II UART adapter v1 is connecting
Posted: Mon May 23, 2022 7:06 am
I'm trying to set up an real-time MPG readout with an Arduino Uno in my 2004 Subaru Outback, and I am not sure if the car and Arduino are communicating properly. Running the built-in LED RPM test doesn't do anything, and the serial output from obd_uart_test doesn't display any of the information it's supposed to:
As far as I can tell from my research, the 2004 Outback uses either ISO9141-2 or KWP2000, both of which are supported by the adapter unless I am mistaken. My end goal is to display MPG on a TM1637-powered 7-segment LCD using this code:
Any ideas or help would be greatly appreciated!
- output2.PNG (14.42 KiB) Viewed 6143 times
Code: Select all
#include <OBD2UART.h>
#include <Arduino.h>
#include <TM1637Display.h>
//set display pins here
#define CLK 2
#define DIO 3
COBD obd;
TM1637Display display(CLK, DIO);
void setup()
{
obd.begin();
// initiate OBD-II connection until success
while (!obd.init());
}
void loop()
{
int k;
uint8_t data[] = { 0xff, 0xff, 0xff, 0xff };
uint8_t blank[] = { 0x00, 0x00, 0x00, 0x00 };
display.setBrightness(0x0f);
//read fuel mass flow rate
int maf;
obd.readPID(PID_MAF_FLOW, maf);
//read vehicle speed
int vss;
obd.readPID(PID_SPEED, vss);
//fancy math to make units good
vss = vss * 710.7;
float mpg;
mpg = vss / maf;
mpg = mpg * 100;
//output mpg to display with leading zeros
display.showNumberDec(mpg, true);
delay(100);
}